SOME FACTS ABOUT FISHES 
45 
Scombridse, represented by tbe Mackerels and Tunnies, of which 
the latter also attain a large size. They have a robust, spindle- 
shaped body, tapering gradually towards the tail, which is an 
exceedingly powerful organ, enabling these fish to travel through 
the water with great rapidity. The two principal genera are 
Xiphias and Histiophorus ; the former, characterized, inter alia , 
by the total absence of the ventral fins, including the Swordfish 
so common in the Mediterranean {Xiphias gladius), which also 
occurs in more northern seas, and is occasionally taken off the 
British coasts ; the latter, in which the ventrals are represented 
by a pair of long, pointed, styliform appendages, being confined 
to the tropical and subtropical parts of the two great oceans. 
In both genera nearly the whole length of the back is occupied 
by a very high dorsal fin (especially elevated in Histiophorus ), 
but which is usually more or less worn away in old specimens ; 
and in both the upper jaw terminates in a long bony spike, the 
so-called sword, formed by the maxillaries, prsemaxillaries, and 
vomer, and projecting far beyond the anterior extremity of the 
lower jaw. This sword, which in large specimens may attain 
a length of two or three feet, with a diameter of two or three 
inches towards its base, constitutes a most formidable weapon, 
with which the swordfish is said to attack whales and wound 
them severely, for what purpose is not known. Sometimes, 
with a gallantry like that exhibited by Bon Quixote in his 
celebrated attack on the windmills, and probably urged by a 
somewhat similar mistaken impulse, the swordfish will assault 
a passing ship or boat, and the power of the fish in the water 
is so enormous that it will drive its weapon a long way through 
even a thick plank. Such exploits, however, are performed at 
the cost of the weapon, for the unfortunate swordfish, being 
unable to withdraw its beak, its struggles to get free, aided 
probably by the motion of the vessel through the water, generally 
break the bone short off. The jaws are toothless. 
The characters presented by the young swordfish for some 
time after their exclusion from the egg are exceedingly different 
from those above described. In general, the changes undergone 
appear to be very similar in the two principal genera already 
mentioned ; but as the series of forms described is more complete 
in the case of Histiophorus , we may take this as our example. 
The earliest phase known in the development of Histiophorus 
is described and figured by Br. Lutken, and is certainly as un- 
like its parents as any young creature would wish to be. The 
specimen measured only about one-fifth of an inch in length, 
and was probably not long out of the egg when it was captured, 
and consigned to the spirit-bottle. The body terminates in 
front in a head much larger in proportion than in the adult 
swordfishes, and tapers off behind the head to a comparatively 
